Radio signaling



Oct. 11, 1932. L, COHEN 1,882,064

RADIO SIGNALING Filed Aug. 50, 1928 Patented Oct. 11, 1932 LOUISFCOHELLVOEVWASHINGTON, nrsrnror or COL BIA Rnnro sreimrrne i (GRANTED unnna rnn'acr or mean 3, 1883; As AM ED APRIL so, 1928; 370 o.-e 757) i The invention described herein may be manufactured and used by or for the Governmentfor governmentalpurposes,without the payment to me of any royalty thereon; I

V This invention relates to the art of radio signaling and particularly to improvements in receiving systems of radio-signals. One

' definite frequencies. v v

object of this invention is to provide methods for the elimination ofinterfering signals of In my copending application, SerialNumber 294,742, filed July23,'1928, I have described a method for the elimination ofinterferences in the reception of radio signals based on the use of a wave-conductorin combination with areceiving circuit system. It

is shown there that by conne'cting'a wave conductor to the antenna, and su tably ad ust1ng the wave conductor in relation to the frequency of an interfering signal, that particular interfering signals may be completely eliminated by the Wave conductor rendering the receiving system proper free to receive signals of other frequencies ,difiering from V the frequency of theparticular interfering signal. Actual experience shows that in such an arrangement it is possible to rece vevsig-n nals of frequencies close to the'frequency-of an interfering signal rendering the interfen,

ing signal practically inaudiblefwhile not nals of slightly difierent frequencies. Without the use of the wave conductortarrang-ewithin applicants experience, a station in r Washington, D.

0., which when tested was operating on 640 kilocycles' came in very loud on the frequency of a New York station which operated on 660 kilocycles. When the in operation, appli- IfVashington station was cant found it impossible even with; the, very station were not and means for'the selective reception of radio signals; another object is to provide-a method length. or an odd impairing the efiiciency of reception oflsiga frequency of the New York station ,and' the strength of the signals of the said New York impaired in theleast. ltavas pointed out in the pendingpatent application referred to above that the wave conductor is tobe adjusted for a quarter wave multiple of quarter .wave lengths andthe extreme end of the wave conductor to remain open. The adjustment-is .tpreferably efiected I by varying the distance separation of a solenoidal coil from a grounded metalplate which together forms whatis called here a wave conductor,=that is one on which a wave d-evel'opmentis effected. Thisiinvention embodies thesame' principle'in amodified form. I find that equally V goodgresults in the matter of interference elimination are obtained by using a waveconductor of approximately double the length,

that is ahalf wave length conductor and grounding the extreme end. The improvements contemplated in this invention willappear evident from the description and-discussion of the accompanying drawing which show typical embodiments of this invention.

:In the'drawingjFigure 1 shows an embodiment of the invention in whichla singleiwave -conductoris used forthe eliminationof an i interfering'signal of a'particular frequency; Y.

In FigureQ a modification 'is shownin which three separate wave conductors .are

used for thesimuiltanous elimination of three interfering signals of-diflferent frequencies; I

Figure 3 a detailed drawing showing a mechanical arrangement for effecting an adjustmentofa, Wave conductor in a View in longitudinalsectionh l l l Having particular 5 reference to the drawing in which the same numbers designate similar parts;

In Figure 1 the antenna 1 is connected to receiving circuit system 2 which is grounded at 3. At the unction point 4 where the antenna connects to the receiving circuit system, there is also connected a wave conductor metal platebeing which consists of a solenoidal coil 5 and a metal plate 6 in proximity to the coil, the

grounded at '3. The opposite end of. the said coil is also groundedas at 3. The operation of the invention as follows: The wave conductor 5, 6, 3, is suitably adjusted "preferably to a half wave length or a multiple of half wave lengths of fected by varying the distance separation of the coil 5 fromthe 4 thereby ,varying th distributed cap acity of the coil. When the proper adjustment is made a zero potential is established for the interfering signal at the junction point where ductors is usualma'nnerr 1 fore it is possible to completely eliminate the effect ofaninterfering signal of a particular .the antenna connects to the wave conductor and receiving circuit system thereby rendering the receiving system free from any interferences by the signals of that particular frequency. V

For any other frequency, the wave' conductor has very little eflect,'if any, and the-receiving'system responds in the With this arrangement there- This is amply borne is in accordance with The embodiment of the invention shown in Figure 2 differs from terfering signals of different frequencies for T which these wave conductorsare 'in'adj ustif mentto affect the receiving circuit system.

This method maybe extended for the elimi'- of each of the interfering signals.

for theadjustm'ent ofaj'wave' conductor, in

which a supporting frame, consisting of up-- rights l3and15 and a base 14:,supports a w H solenoidal coil comprising a core 16 and wire' nectionofsaid' antenna to said receiving c r- 16" wrapped there'about. An adjustable cuit system, the" other 'endbeinggroimde'd,

I claim: the interfering signal, the adjustment is af-i grounded metal plate 6,

however,

signals Figure 1 in that three' f .separate wave-conductors 7, 8 9, 10; 11', 12; are connecte'dat one end to the junction point 4' where the antenna connects with the re ceiving circuit system. Thefiopposite ends .of each ofthese waveconductors are-sepa- -Irately groL1n-ded.- Each of these wave conseparately adjusted to the. --frequency of a different" interfering signal 56 thereby preventing any ofthree different in- 1 metal plate 17 is liingedly connected to the sidewall 13 by means of a pin 21. As a means of adjusting the plate 17 there is provided a screw bolt 18 rotatably mounted in the base 14:. A nut 20 is mounted on the screw threads of the bolt 18 and the nut 20 is connected by means of a fork 22 to the plate 17. Thus a rotation of the bolt 18 by the turning of the knob 19 results in a vertical movement of the plate 17 on its hinge and the, consequent variation in the separation distance of the plate from the solenoidal coil, the purpose of which ad ustment is apparent in the foregoing description. .1;

"1r Ina system for the reception of radio signals, compr sing ,an' antenna, a .receiving circuit system connected thereto, and a waveconductor, said wave conductor being adjustable' to the frequency of an interfering 'signal,said waveconductorcomprising af's'olenoidal coil placed in proximityxto a grounded metal plate, 'one 'endof said wave conductor being connected to the junction point of connection of saidantennato said receiving circuit}. system, and the other end being grounded, the adjustment of said. wave conductor being effected by varying the distance SGPaIafiIOn of said solenoidal coil from said grounded" metal plate.

'2. In *a system for-the reception of'radio signals, compr slng an -antenna,;alreceivmg circuit system-connected thereto, a Wave conductor havingone of itsends-connected at the ]L1IlCtlQI1:pOlI1t of connection of said antenna to said receiving circuit system,

the other end being 'grounded, said wave con- ;ductor being adj ustable to a half-wave length of an interfering'signal. W

'adjustable'to' a multipleof half-wave lengths of an interferingsignali 4; -a systemfor the receptionof radio s gnals, compr sing-an antenna, a receiving circuit system connected thereto, a plurality of Wave conductors eachhaving one-1en dcon- I n'ected at. the 'junctionpoint of connection of nation of interferences from any number'of" transmitting stations-by the simple expedient of connecting atAa number of wave con--" ductors each separately adjusted to afrequency I Figure 3 is a detailed drawing showing a cross section of a mechanical arrangement said antenna "to said receiving circuitsystem, the other end being-grounded,'each of iifering' signal. c

5. ln-afsystem for the reception aria-C f'signals, comprising an antenna, a receiving" circuit system connected thereto, aplurality of wave conductors QEI'ClliOf which "hasone end" connected to .thejunction point :of con- 3. In a system f'r-the reception of radio slgnals, comprising an antenna, a receiving said receivingcircuit system, the other end 1y adjustable to a multiple of ha f-wave each of said wave conductors being separately adjustable to a half-Wave length of an interfering signal.

6. In a system for the reception of radio signals, comprising an antenna, a receiving circuit system connected thereto, a plurality of Wave conductors each of which has one end connected at the junction point of connection of said antenna to said receiving circuit system, the other end being grounded, each of said Wave conductors being se aratelengths.

In testimony whereof I aflix my signature.

LOUIS COHEN. 

